Adding features to make it easier to build screens like this is on our road map. For now, there might be workarounds depending on the use case you have. Most use case have a reasonable workaround.

For example, can you get away by using a Grid component?

Your screen would look like this:

Column A Column B Column C
Field A Field B null
null null Field C
Field A Field B null
null null Field C

And you can show a display-only null value (or you can even hide the component altogether) in each row depending on which fields are relevant.

This does not look as pretty as what you have in mind but if you view it as a temporary workaround then maybe it's acceptable? (You'd replace this screen with the one you have in mind, when the appropriate features are available in Formspider.)

I can do something like that.... at the moment all the fields are display only, but field C could be a large number of charaters and would need to span across multiple columns.

The plan I have come up with so far, is to have a grid of a single column (2000 charaters) and use a fixed width font such as courier, rpad the columns A and B in one row and put field C in the next row so on and so on

I'm thinking that will work, until they decide they need the ability to update the data in the same screen.